18 Comments
Jan 25Liked by Dan Heller

Once again, you've written an extremely thought-provoking article. Thank you for putting this together!

I've had T1D for 45 years. I use Control IQ and I (1) love it and (2) don't disagree with your conclusions in the least. I'm meticulous about bolusing for food and high blood sugars. Without that effort, the pump wouldn't be effective at all.

Why do I love it? For me, it's COMPLETELY eliminated overnight lows since the day I switched to CIQ. I used to run high at night out of fear of those overnight lows. No longer! I wake up every morning at 110 mg/dl. This is the one area where closed loop tech is (understandably) excellent. When a diabetic is asleep, the pump can simply release basal insulin, adding more or giving less as needed. Without meals or exercise or stress to worry about when the patient is asleep, it's pretty hard for CIQ to mess up. That alone is worth it for me. But nothing I'm saying contradicts your conclusions.

Thanks again. I look forward to reading each of your posts.

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Jan 28·edited Jan 28

Proofreading Police! 😉

“Technically, such a system a highly“

You’re missing a verb, perhaps “is”?

“Another way to test that is by measuring A1c levels before and after introducing people to pumps and measuring their outcomes afterwards (while including subjects from diverse social, racial and economic subpopulations). This metaanalysis (literature review) of dozens of RTCs had these aims in mind, and also included”

Please, sir, what are RTCs?

Policing over. Again, thank you for an interesting article. I always learn something from your posts. I'm a Metronic user and I got a new pump over a year ago. They gave me a box of sensors and a chance to try out this new 780G system. Well, I have a problem with rising blood sugar after I get out of bed. I like to eat right away, so first thing I do is check my numbers and enter carbs for breakfast. However, auto mode thought that my rising blood sugars were from eating, but I knew they weren't. So I had to exit auto mode, bolus in manual mode, and then go back to auto mode a few hours later for the rest of the day. I learned from a forum that I could "phantom bolus" to correct, but it just seemed a hassle. It was way easier to set my Basals where they needed to be. Plus, I would have to pay out of pocket for the sensors, when the Libre 2 was covered by the government.

I missed my old pump, because the new one was specifically designed to be used in auto mode and manual mode requires seemingly endless button pressing. Unfortunately, I forgot to take that old pump off when I went swimming in the sea. "Critical Error!" ;-) So, back to my "back up", newer pump.

My 2 months on the Medtronic "closed loop" system was very frustrating and my time in range numbers were worse. I can see where it would be advantageous for someone who was hypo unaware, especially at night, but it just wasn't working for me.

I look forward to your next article.

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Thanks so much for combing through the studies’ detail and summarizing smartly for us. I am personally so grateful since I have for 2 years tried hard to stick with a pump and yet conclusively proved to myself with a full 90-day MDI experience (post pumps) that MDI is more liberating and educational and effective. I had an amazing 5.6 A1C and proved my instincts are right. Plus, I do keep learning, which helps alleviate fears of lows and navigate the exercise-related challenges in different scenarios like seasons and temperature and such. I feel like pumping was sort of favored by my health practitioners, though not any longer as they now let me experiment with very fast-acting insulins, dosing regimens and really support anything I want to try (I am deeply motivated to stay healthy at age 60 and to find balance, which I am now working toward by trying to let go all my daily record-keeping and ritual of data-study every morning to make basal dosing decisions and such). This article and, indeed, all that I have read here, feels so supportive of my innate approach to diabetes management. I have felt asea on some pump-oriented forums, and even “bold with insulin” approaches that have led to some very real scares. Thank-you so much for the wisdom, authenticity and help here. I have also been struggling with decisions on Freestyle Libre 3 (always accurate to 5 points compared to meter - though should be a lag, I suppose) versus Dexcom g6 (needing multiple calibrations this whole past year, but love the data, Clarity App and realize the frequent reporting of L3 can cause rash wrong decisions versus every 5 minutes). Still trying to see which one will be better and what I would give up. G6 constantly runs 40 points low during and after exercise in cold weather, but can I learn to just react with glucose at a different, so-called wrong number and which will give better peace of mind? Crazy, but I think g6 could lead to smoother life, though hate finger-sticking. So all that wordiness to say, I am beyond grateful how all of this that you give us feeds me so personally as I try to learn. I am only 3 years into this drastic change of life and how I can proceed and become free within its constraints and let go fear. I am lucky to have always prized health and had my exercise, water and meal-times already set as stable. I don’t have time to err too much and have needed this information and perspective to be shared with me. Sorry, this was so long winded, but just want to share my appreciation and how personal this is. Thank you so much.

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Hi Dan, this is an interesting article, but I feel as though you're conflating two separate issues. Pump therapy and automation, which I think are two different (but linked) items.

The majority of the studies showing greater issues with pump therapy that you've referred to talk about traditional pumps rather than Automated Insulin Delivery devices. If users consider traditional CSII to be automated devices rather than devices that replace MDI with a more flexible delivery system that still requires equivalent levels of user interaction (meals, exercise and illness being the key ones), then who is at fault? The user or those who provide the alternative delivery system to them without appropriate introduction and education?

Automation without knowledge of what to do without it, on the other hand, does present potential problems. Even then, nothing that's on the market right now should be considered as anything other than hybrid closed loop, requiring intervention for both meals and exercise, and if users aren't using it that way, then again we come back to the question of why not? Is it down to the user, the technology or the environment in which it is deployed?

While the person manages the diabetes, if technology frees up headspace requiring less user oversight and results in the same numbers, I don't see that as an issue, even if one is capable of taking care of themselves to a high level without using it.

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Some of this reminds me of findings about autopilots in the airline industry showing that pilots not having enough to do leads to inattention that in turn causes problems when intervention by the pilot is necessary. But that leads to something that's kind of a hobby-horse for me (T1 since 1983) around AID systems and that gets touched on here. Namely, is the ideal to have a black-box, set-and-forget system that does everything for you? That seems to be the assumption in this article, but my experience with these systems, having been on both Medtronic and Tandem, is that there are two design philosophies in play. The Tandem seems to be more a kind of smart assistant that offers options and can do corrections when things get off balance but doesn't want to assume complete control, where the Medtronic approach was very much more that of a HAL9000 ("I'm sorry Dave. I can't let you do that.") I think the Tandem approach is much more in line with inherent limitations of the whole problem.

Other stuff:

> CGM vs Pump. I've said many times that if I had to choose between the two, I'd give up the pump before I gave up the CGM hands down. So yeah. But I still think there are real quality of life considerations. Such as....

What pumps are really for: solving the basal conundrum.

I was on R/NPH for 20 yrs, then Basal/Bolus MDI for 10 before starting with a pump in 2004, pre-CGM. Until then I was NEVER able to get ahead of Dawn Phenomenon, and struggled hugely to accommodate exercise, unanticipated overnight excursions and the like. Even with a "dumb" pump, being able to program steps in your basal delivery to accommodate more-or-less predictable diurnal changes in your basal BG output is a huge lifestyle improvement as well as management. You can't turn Lantus OFF when you want to go for a bike ride or have to run to catch a bus. To me this flexibility is 80% of the justification, leaving aside Christmas tree bells and whistles. I was surprised not to see this given more emphasis.

Outcomes vs quality-of-life

I was pleased to see q-o-l treated as a significant consideration here, as it is so often left out in favor of "outcomes" that are more reducible to numbers. The basal control issue is the most significant for me in terms of this. I grant that there are many more options now than good old Lantus, but essentially they all have the same problem: the "resolution" can only vaguely conform to diurnal cycles, which are largely predictable and thus amenable to a programmable delivery system, even a "dumb" one, and being able to adjust in light of unforeseen events is a huge benefit to leading something resembling a normal life. Like I say, I was on R/NPH, which for good reason I used to refer to as the "East now or DIE!" regimen, so I'm very sensitive on this issue. If the data says my A1C isn't all that much better I'd still respond that A1C isn't the only measure I care about.

A last thing I don't see here that I think is worth mentioning: insulin speed. I've gone from Regular to Novolog/Humalog to Fiasp. Fiasp is noticeably faster for me, but there's still a frustratingly long lag time, especially when it comes to correcting a post-prandial that's gotten out of control. I know people who speak highly of Afrezza but inhalable insulin can have other problems. Mainly I'm thinking about the flaws with AID and pumps in general, where the issue for me hasn't really been about the programming or CGM accuracy as just how slowly **any** of these systems can respond to BG changes due to the effect curve of the insulin itself as well as the inherent inefficiancy of subcutaneous injection vs a functional pancreas attached to your bloodstream. To me this is the limiting factor in the way of a true "black-box" device and why I prefer a system that doesn't overpromise what it can actually achieve.

Anyway, thanks again--lots to think about and links to follow up here. This represents a lot of work pulling sources together and I think it's a real contribution to our understanding.

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